A Reconnaissance Survey Of Tobin Lake

Transcription

1 A Reconnaissance Survey Of Tobin Lake A. R. McLean 1990 PWFWCP Report No. 95

2 The Peace/Williston Fish & Wildlife Compensation Program is a cooperative venture of BC Hydro and the provincial fish and wildlife management agencies, supported by funding from BC Hydro. The Program was established to enhance and protect fish and wildlife resources affected by the construction of the W.A.C. Bennett and Peace Canyon dams on the Peace River, and the subsequent creation of the Williston and Dinosaur Reservoirs. Peace/Williston Fish and Wildlife Compensation Program, 1011 Fourth Ave. 3 rd Floor, Prince George B.C. V2L 3H9 Website: This report has been approved by the Peace/Williston Fish and Wildlife Compensation Program Fish Technical Committee. Citation: A. R. McLean A reconnaissance survey of Tobin Lake. Peace/Williston Fish and Wildlife Compensation Program, Report No pp plus appendices. Author(s): Allister R. McLean 1 Address(es): 1 Peace/Williston Fish and Wildlife Compensation Program, 1011 Fourth Ave., 3rd Floor Prince George, B.C. V2L 3H9

3 A RECONNAISSANCE SURVEY OF LAKE WATERSHED: DATE OF SURVEY: FIELD CREW LEADER: FIELD ASSISTANT: Finlay River August D.A. Jesson A.R. McLean PEACE FISHERIES COMPENSATION PROGRAM B. C. HYDRO ENVIRONMENTAL RESOURCES and B.C. ENVIRONMENT FISH AND WILDLIFE BRANCH REPORT PREPARED BY: A.R. McLean RELEASED BY:

4 LAKE: Tobin SYSTEM NAME: Unnamed C. A.S.A.P. REFERENCE NO.: DATA ON FILE FOR THIS SURVEY Location Physical Data Bench Mark Terrain Features Access Resorts and Campsites Other Developments Obstructions and Pollutions Special Restrictions Aquatic Plants Wildlife Observations Miscellaneous Comments Lake Drainage Fisheries Management Comments History of Previous Surveys Water Chemistry Summary -- SYSTEM NO: Dissolved O2/Temp. Profiles Winter Dissolved 02/Temp. Profiles Netting Record Lake Catch Summary Individual Fish Data Fish Preserved Stomach Analysis Scale Reading Location of Inventory Sites Photograph Directory Appendices: A: Water Chemistry Analysis B: Tributary Stream Data Bathymetric Map Reduction Bathymetric Map LOCATION Location: Elevation: Latitude/Longitude: Management Unit: 135 km northwest of Mackenzie 740 m +/ '08":124 10'45" U.T.M.: N.T.S. Map No.: 94-C/8 (edition 1) Drainage: Outlet C. --> Lafferty C. --> Williston Reservoir (Finlay Reach) --> Peace R. PHYSICAL DATA See Webber T. and B. Tupniak, BENCHMARK (Iron spike, center of red circle) Previously set benchmark (1981) located in a 32 cm diameter birch tree. Benchmark is now 1.13 m above present water level. An 87 cm rise in lake level is apparent. High water mark: Lake is at maimum pondage.

5 TERRAIN FEATURES Immediate Shoreline: See Webber, T. and B. Tupniak, The increased water level has flooded (appro. 2-5 m) previously "dry" shoreline vegetation making access to or from water difficult at these locations. However, boating in shallows and at survey access point has improved with the elevated water level. A fringe of Potamogeton sp. and water grasses etends up to 6 m into the lake. Surrounding Country: See Webber, T. and B. Tupniak, Clearcut patches are visible to the southeast from the southeast corner of the lake. Tobin Lake is located in the sub-boreal spruce biogeoclimatic zone.

6 ACCESS Directions: From the weigh scale at the Ospika logging camp, travel northeast 12.8 km on the Finlay Davis Forest Service Road. Lake is located to the right. (Access to Ospika logging camp is by barge or air only). Alternately, from the entrance gate at Fort Graham Lodge, travel 1.6 km to the Finlay Davis Forest Service Road. Turn right and proceed south 29.3 km to Tobin Lake. Lake is located to the left. Total distance from Ft. Graham Lodge (entrance gate) to Tobin Lake is 30.9 km. Road Type and Conditions: Finlay Davis Forest Service Road is a good, all weather, gravel two lane logging road. Restrictions: None. RESORTS AND CAMPSITES None. OTHER DEVELOPMENTS See Webber T. and B. Tupniak, A trail is present along the north shore of the lake.

7 OBSTRUCTIONS AND POLLUTIONS Beaver dams on the inlets and outlet appear to be barriers to upstream fish passage. Numerous other beaver dams are present on Lafferty C., some of which appear to be barriers to upstream fish passage. SPECIAL RESTRICTIONS None. AQUATIC PLANTS See Webber, T. and B. Tupniak, 1981, WILDLIFE OBSERVATIONS 2 loons MISCELLANEOUS COMMENTS An unidentified fish species (minnow) was observed in the pond created by beaver dam #1 on inlet #1. A logging road now parallels the south shore of the lake.

8 LAKE DRAINAGE General: Tobin Lake has two inlets and one outlet. The outlet flows appro. 0.2 km west to Lafferty C. Lafferty Creek flows appro km northwest to it's confluence with Williston Reservoir (Finlay Reach). Major Systems: None. Minor Systems: Unnamed C. - inlet #1 The initial 1.1 to 1.2 km of this creek was investigated. Inlet #1 drains through a marsh area into the east shore of Tobin Lake. Beaver dam #1 (22 m in length by 1 m in height) is located appro. 600 m upstream from the lake. The dam is believed to have been blown and the creek rediverted to an old trappers cabin at one time. The dam has long since been rebuilt and flow is still present near the cabin (cabin no longer in use). A second beaver dam (4.5 m in length by 1 m in height) is located appro. 700 m upstream of the lake. Further beaver dams are located at appro. 850 m and 925 m upstream of the lake. This inlet has virtually no flow and a complete organic substrate, subsequently no spawning habitat is available. Unnamed C. - inlet #2 This inlet flows m from a small lake/swamp into the north shore of Tobin Lake. The inlet has a total vertical drop of appro. 2 m, an average wetted width of 36 cm and an average depth of 5 cm. No spawning or rearing habitat is present. Unnamed C. - outlet The lake level is controlled by a beaver dam (appro. 60 m in length by 1.5 m in height) located at the outlet (appro. 300 m downstream of the main lake body). Numerous beaver dams are located further downstream on the outlet C. This creek affords no salmonid spawning potential.

9 FISHERIES MANAGEMENT COMMENTS Tobin Lake supports a population of rainbow trout and assorted coarse fish. A 25 hour net set and 2 minnow traps captured 2 rainbow trout and 3 different coarse fish species (redside shiner, lake chub, coarse sucker). Inlet #2 affords no spawning or rearing habitat. Inlet #1 and the outlet afford no spawning potential as a result of etensive beaver activity. The lake level is controlled by a beaver dam (60 m in length by 1.5 m in height) located at the lake outlet. Removal of this dam would concentrate the fish population into one area and seriously affect boating (see Webber, T. and B. Tupniak, 1981). Hydrogen sulphide was evident (> 5 mg/l) from a water sample taken at a depth of 30 m. Summer and winter oygen results suggest that only the upper 7 m of the water column is capable of supporting a fish population. This lake is suitable for a sportfish introduction. A piscivorous strain of rainbow trout could be considered as large quantities of minnows were captured during the investigation. In addition to the potential of gravel placement on inlet #2, the lake/swamp at the head of the inlet may be utilized to ensure adequate water supply for spawning at times of low flow. This could relieve a potential spawnbound condition and provide natural recruitment, should this lake be stocked. However, further detailed investigations are required to assess the enhancement potential of this inlet. Post Survey Note: Tobin Lake was stocked September 18, 1989 with 17,000 rainbow trout (Dragon Lake Stock). Average weight was 1.09 grams. HISTORY OF PREVIOUS SURVEYS Lake Surveys: Webber, T. and B. Tupniak, A Reconnaissance Survey of Tobin Lake. Report on file at B.C. Environment, Prince George. Other Related Surveys: A winter oygen/temperature series was collected on February 27, 1990 by D.A. Jesson, Peace Fisheries Compensation Program, Prince George, B.C.

10 WATER CHEMISTRY SUMMARY Limnology Station No. 1 Field Conditions: Date: August 29, 1989 Time: 1330 hrs Air Temperature: 22.5 C Wind Velocity: 0-2 km/hr Wind Direction: northwest Cloud Cover: 1/10 o.c. Surface Condition: flat Secchi Disc: 3.9 m Water Colour: tannic Method(s) Used: Dissolved Oygen: Water Temperature: Air Temperature: ph (field): H2S (field): Laboratory Used: Water Sampler: Substrate Sampler: YSI model 58 oygen/temperature meter YSI model 58 oygen/temperature meter Hand-held alcohol thermometer Hach ph tester Hach H2S field test kit Zenon Environmental Inc. B.C. Laboratory Services Verticle Alpha Water Bottle (Vandorn) Substrate sample not taken Water Sample Chemistry: SEAM Site No.: to be determined later. ph (field) ph (lab) Specific Conductance (lab) Filterable Residue 105 C (lab) H2S (field) Bottom Depth: Substrate Sample Depth: Sampling Depths Surface (O m) Lower (30.0 m) O 36.0 m umhos/cm mg/l mg/l m umhos/cm mg/l > 5.0 mg/l Strong hydrogen sulphide odour noted.

11 DATE: August 28, 1989 SUMMER OXYGEN/TEMPERATURE DATA DEPTH (m) Surface (mg/l) Bottom TEMP TO NOTE: No readings taken below 8.5 m. This was done to avoid potential damage to the 02/temp sensor caused by hydrogen sulphide.

12 WINTER DISSOLVED OXYGEN AND TEMPERATURE SERIES Dissolved Oygen (mg/l) Temperature ( C)

13 Date: Time: Air temp.: Wind: February 27, hrs O C Crew: D.A.Jesson/B.Westcott Snow depth: 5 cm Ice Depth: 100 cm Weather: WINTER OXYGEN/TEMPERATURE DATA DEPTH (m) Surface (mg/l) Bottom TEMP ( C)

14 WINTER DISSOLVED OXYGEN AND TEMPERATURE SERIES Dissolved Oygen (mg/l) Temperature ( C)

15 NETTING RECORD Mesh sizes eperimental order: 25, 76, 51, 89, 38, 64 mm NETTING SITE #1 Type: Sinking monofilament Date Set: August 28, 1989 Date Lifted: August 29, 1989 Net Dimensions: Length: 91.4 m Shallow End Mesh Size: 25 mm Deep End Mesh Size: 64 mm Time: Time: Depth: Depth: Substrate: Depth: Substrate: 0950 hrs 1100 hrs 2.4 m 3.0 m organics 25.0 m organics Comments: All fish captured in the 25 mm and 76 mm mesh sizes. This is probably because the other mesh sizes were set below minimum oygen requirements.

16 LAKE CATCH SUMMARY SPECIES 1 NET SITE NO ANGLED OTHER TOTAL NUMBER SAMPLED NUMBER PRESERVED SIZE RANGE (cm) rainbow trout redside shiner lake chub coarse sucker Comments: A large quantity of the redside shiners stomachs were swollen with large tapeworms Minnow Traps: BAIT: Sardines # HOURS DEPTH (m) SUBSTRATE SPECIES SIZE RANGE (cm) organics 37 redside shiner 23 lake chub 1 coarse sucker organics 69 redside shiner 21 lake chub Comments: Blackspot disease noted on some redside shiners and lake chub.

17 Tobin INDIVIDUAL FISH DATA Date Captured: August 28, 29, 1989 Method of Capture: Sinking monofilament gillnet M - Male F - Female? - Not Obvious IMM - Immature MG - Maturing MT - Mature GV - Gravid SP - Spent? - Not Obvious EG - Egg FR - Fin Ray HD - Head ML - Milt OT - Otolith SC - Scale ST - Stomach TG - Fish Tag WF - Whole Fish SPECIES Fork Length (cm) Weight (grams) Se Gonadal Maturity Sample Type Age (yr) Stomach Contents Plankton Insects Fish Other COMMENTS rainbow trout F MT sc 2 + lake chub tapeworms eggs reabsorbing rainbow trout M MT sc 4 + unidentified fish parts tapeworms in gut tapeworm nodules on stomach AGE DETERMINATION COMPLETED BY: D.A. Jesson, Peace Compensation Program, Prince George, B.C.

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19 PHOTOGRAPH DIRECTORY Negative # Plate # Description R12:23A,24A 1 Panoramic view of Tobin Lake, looking southeast, taken from west shore of lake. R12:22A Upstream view of inlet #1 marsh, taken appro. 75 m upstream from main lake body. Clearcut is visible to the right. R12:18A View of beaver dam #1, on inlet #1, taken appro. 600 m upstream from lake. R12:19A Upstream view of beaver dam #2, on inlet #1, taken appro. 700 m upstream from lake. R13:4A Downstream view of beaver dam (appro. 60 m in length by 1.5 m in height) at lake outlet, taken from lake. This dam controls current lake level. R13:3A Downstream view of outlet C., taken appro. 200 m downstream of lake. *Not shown on map.

20 Plate 1: Panoramic view of Tobin Lake, looking southeast, taken from west shore of lake.

21 Plate 2: Upstream view of inlet #1 marsh, taken appro. 75 m upstream from main lake body. Clearcut is visible to the right. Plate 3: View of beaver dam #1, on inlet #1, taken appro. 600 m upstream from lake.

22 Plate 4: Upstream view of beaver dam #2, on inlet #1, taken appro. 700 m upstream from lake. Plate 5: Downstream view of beaver dam (appro. 60 m in length by 1.5 m in height) at lake outlet, taken from lake. This dam controls current lake level.

23 Plate 6: Downstream view of outlet c., taken appro. 200 m downstream of lake. *Not shown on map.